Carbamoyl phosphines and preparation thereof



United States Patent M 3,214,457 CARBAMOYL PHOSPHINES AND PREPARATIONTHEREOF Grace Peters Papp and Sheldon A. Buckler, Stamford, Conn.,assignors to American Cyanamid Company, Stamford, Conn., a corporationof Maine N0 Drawing. Filed Sept. 11, 1963, Ser. No. 308,083 11 Claims.(Cl. 260-4654) The present invention relates to novelcarbamoyl-disubstituted tertiary phosphines and oxides of the formulaRlRzP o ONHZ These compounds are prepared generically as follows RR2PH+(is0)cyanic acid R1R2PO0NH2/+O RiRzf CONlTz R and R in the aboveformulae represent substituted and unsubstituted, saturated andunsaturated, branched and straight chain alkyl having from 1 to 18carbon atoms, substituted and unsubstituted cycloalkyl, such ascyclohexyl and cyclopentyl, substituted and unsubstituted aryl, such asphenyl and naphthyl, and n is 0 or 1.

The reaction described hereinabove is best carried out in an aqueousmedium at a temperature in the range of, preferably, 22 C. to 110 C.However, temperatures in the range of C. to about 200 C., or more, arecontemplated herein.

It is essential that the reactions of the present invention be performedunder substantially anaerobic conditions, such as under nitrogen or asimilar inert gas, if the tertiary phosphines are desired. Of course,the presence of a significant amount of air or oxygen results in thecorresponding tertiary phosphine oxide being produced direct-ly. Forexample, recovery in an open vessel provides the requisite amount ofair.

While an aqueous medium is preferred, non-aqueous conditions using aninert organic solvent, such as CH CN, tetrahydrofuran, dioxane, dimethylether of ethylene glycol, and the like, may be employed.

Typical secondary phosphines R R PH within the purview of the presentinvention are dimethylphosphine, dioctylphosphine, didodecyl-phosphine,diisobutylphosphine, diethylphosphine, bis(trifluoromethyl)phosphine,diphenylphosphine, dibenzylphosphine, bis(2-butoxyethyl)phosphine,bis(parachlorophenyl)phosphine, bis(paramethylphenyl)phosphine,bis(2-cyanoethyl)phosphine, dicyclohexylphosphine,dicyclopentylphosphine, dioctadecylphosphine, and the like. It followsfrom the above representative list of secondary phosphine reactants thattypical substituents therefor are cyano, lower alkyl, phenyl, halogen,lower alkoxy and the like. characteristically, these and like'substituents are inert under the reaction condi v tions contemplatedherein.

The (iso)cyanic acid reactant may be introduced into the reactantmixture or it may be generated therein (in situ) by any conventionalmanner. For instance, an alkali metal derivative of (iso)cyanic acid,such as KOCN, NaOCN, and the like, may be admixed with the phosphinereactant in the presence of an acid and (iso)cyanic acid thus liberated.Typical useful acids are mineral acids, such as HCl, HBr, H 80 and thelike, organic acids, such as acetic acid, propionic acid, and the like.

The reactions of the present invention may be carried out underatmospheric, sub-atmospheric or super-atmospheric conditions. Thesequence of addition of the reactants is not critical and the reactionmay be batch, semicontinuous or continuous.

The ratio of reactants is likewise not critical. While 3,214,457Patented Oct. 26, 1965 practicality dictates about equimolar amounts ofsecondary phosphine reactant and (iso)cyanic acid, an excess of eitherreactant with respect to the other may be employed.

The corresponding oxides of the tertiary phosphines produced herein mayalso be prepared as described in copending application Serial No.824,169, now US. Patent 3,145,234, issued August 18, 1964, by the use ofa peroxide, such as hydrogen peroxide, dinitrogen tetroxide. Reaction iscarried out with significant case. This copending application isincorporated herein by reference.

The novel monocarbamoyl-substituted tertiary phosphine and phosphineoxides of the present invention, prepared as described above, havedirect utility as flameproofing agents. For instance, cotton cloth maybe immersed in a suitable solution containing a small amount (e.g. from0.5% to 10%) of any one of the novel compounds of the present invention,and the cloth subsequently dried. The thus-treated cotton cloth exhibitsdesirable fire retardance on direct contact with a flame.

The present invention will best be understood from the followingexamples:

EXAMPLE I Dibutylcarbamoylphosphine oxide Under nitrogen, 7 grams ofacetic acid is added dropwise to a mixture of 4.4 grams ofdibutylphosphine, 5.0 grams of dry, freshly ground KOCN and 1 cubiccentimeter of pyridine in 50 cubic centimeters of CH CN at 60 C. C. Themixture is heated at reflux for 2 hours, then cooled and filtered. Airis blown through the filtrate for 3 hours, and 1.0 gram of product,dibutylcarbamoylphosphine oxide, precipitates. Concentration of thefiltrate and subsequent addition of petroleum ether affords anadditional 1.1 grams of product, dibutylcarbamoylphosphine oxide,melting point 160 C.170 C.

Recrystallization from benzene gives an analytical sample, melting point177 C.178 C.

Calculated for C, 52.67; H, 9.82; N, 6.82; P, 15.09. Found: C, 52.46; H,9.86; N, 6.86; P, 14.90.

EXAMPLE II Carbamoyldicyclohexylphosphine Carbamoyldicyclohexy[phosphineoxide A solution of 12 grams of KOCN in 35 cubic centimeters of H 0 isadded, under nitrogen, to a mixture of 12 grams of dicyclohexylphosphinein cubic centimeters of acetic acid at 70 C.-80 C. The reaction flask isremoved from the oil bath as substantial foaming begins and a voluminousprecipitate deposits. After stirring for 3 hours, the resulting mixtureis filtered, solid product carbamoyldicyclohexylphosphine precipitateswhich is washed with water and dried in a desiccator, 12.7 grams ofsolids, melting point 121 C. C., being obtained. Analysis of the crudeproduct yield is the fol-lowing: Calculated for C, 64.67; H, 10.03. H,9.93.

Attempted recrystallization from hexane containing a small amount (about5 percent) of methanol causes conversion to the corresponding oxide,carbamoyldicyclohexylphosphine oxide, melting point 177 C.179 C.Analysis calculated for C, 60.68; H, 9.40; N, 5.44; P, 12.04. Found: C,60.36; H, 9.61; N, 5.55; P, 12.19.

EXAMPLE III Carbamoyldiphenylphosphine carbamoyldiphenylphosphine oxideA solution of 7.4 grams of diphenylphosphine in 40 cubic centimeters ofacetic acid is treated, under nitrogen, with 6.5 grams of KOCN in 20cubic centimeters of H 0. After 1 hour at reflux, two layers form whichFound: C, 64.07;

are separated when cooled. The lower layer (about 50 cubic centimeters)is poured onto 200 cubic centimeters of H 0. After standing, 2.4 gramsof product carbamoyldiphenylphosphine (26 percent) precipitates. Re-

cyclohexyl, substituted and unsubstituted phenyl, wherein thesubstituents for alkyl are selected from the group consisting of cyano,phenyl, halogen and lower alkoxy and the substituents for phenyl areselected from the crystallization of this product from 2:1benzene-hexane 5 group consisting of cyano, lower alkyl, halogen andlower gives an analytical sample, melting point 115 C.116 C. alkoxy, andn is selected from 0 to 1. Analysis calculated for C, 68.12; H, 5.28; N,6.11; 2. Carbamoyldibutylphosphine oxide. P, 13.52. Found: C, 68.04; H,5.59; N, 5.93; P, 13.45. 3. Carbamoyldicyclohexylphosphine.

Addition of the upper layer to water deposits 1.5 grams 4.Carbamoyldiphenylphosphjne. of solid, which on recrystallization from abenzene and 5. Carbamoyldiphenylphosphine oxide. hexane mixture has amelting point of 190 C.l91 C., 6. Carbarnoyl-bis(Z-cyanoethyl)phosphineoxide. and analyzes as carbamoyldiphenylphosphine oxide. 7. A methodwhich comprises bringing into reactive Analysis calculated for C, 63.67;H, 4.93; N, 5.71. contact under substantially anaerobic conditions asec- Found: C, 63.32; H, 5.48; N, 5.76. ondary phosphine of the formulaEXAMPLE IV Carbamoyl-bis(Zwyanoethyl)phosphine oxide RIRZPH A solutionof 14 grams of bis(z cyanoethyl) phos and (iso)cyani c acid andrecovering the corresponding phine in 40 cubic centimeters of aceticacid is treated, ternary PhosPhlne of the formula under nitrogen, with16.2 grams of KOCN in 27 cubic centimeters of water at 60 C. Afterevolution of gas R1R2PCONH2 has ceased, the solution is cooled andtreated with 10 R1 and R2 in the above formulae each representing a 9 2centimeters of concentrated K2504 ber selected from the group consistingof substituted and climates and 1s filtcfred and filtraie FYaPol-atedunsubstituted alkyl having from 1 to 18 carbon atoms, to dryllessExtracnon of the resldue Wlth bolhng meth cyclopentyl, cyclohexyl,substituted and unsubstituted gwes grams of l cal'bamoyk phenyl, whereinthe substituents for alkyl are selected bls(z'cganoethynphmpllme oxldemeltmg pomt from the group consisting of cyano, phenyl, halogen andQ7171 An analymcal.sampleo thereof orecrystalhzes lower alkoxy and thesubstituents for phenyl are sefrom methanol melimg pomt 179 G480 and haslected from the group consisting of cyano, lower alkyl, the followinganalys1s: Calculated for C, 42.21; H, 5.06; halogen and lower alkoxy gFound: 4254; 4'92; 20'81; 8. The process of claim 7 wherein saidtertiary phosphine product is reactively contacted with an oxidizingEXAMPLES V Xv agent to form the corresponding tertiary phosphine oxideThe following table further illustrates the present inof the formulavention, reaction having been made to take place essentially as inExample I, above, except as indicated in the 11 table. RiRaPCONH;

TABLE I II RIRgPH (1so)eyanic acid R1RaPCONH I+ O RiRzPOONH,

Example R1 R (Iso)cyanic acid Temp., Water Solvent R1 R2 oxidizing agentR1 R1 source O.

V Dimethyl KOQdN-l-acetic 10 H2O"-.. Dimethyl Hydrggen per- Dimethyl.

3.01 0X1 e. VI Dioctyl NaOCN+pro- H2O.--" Dioctyl Air. Dioctyl.

pionic acid. VII Dibenzyl KOCN-i-prg- 70 None.-.. CH3CN- Dibcnzyl doDibenzyl.

plomc acl VIII Dicyclopentyl (Iso)cyanic acid None CHsCN Dicycl0pentylH2504 Dicyclopcntyl.

gas. IX Bis(paramethy1- do None Dioxane Bis(pa.ramethyl- Air-Bis(paramethylphenyl). phenyl). phenyl). X Bis(tritluoro- KOCN-l-acetic40 None Tetrahydro- Bis(trifluor0- do Bis(trifluoromethyl. acid. iuran.methyl). methyl). XI Didodecyl Na0ON+HC1 Didodecyl Hydrtgen per-Didodecyl.

on e. XII Diisobutyl KOCN+HC1. 60 Diisobutyl Air Diisobutyl. XIIIBis(2-cyanoethyl) (Iso)cyanic acid 42 Bis(2-cyanoethyl). --d0Bis(2-cyanoet-hyl).

gas. XIV Bis(parachlorodo 78 Bis(parachloro- ---d0 Bls(parachlorophenylphenyl phenyl). XV Bis(2-butoxydo 20 Bis(2-butoxydo Bis(2-butoxyethyl)ethyl). ethyl).

wherein R and R each represent a member selected from the groupconsisting of substituted and unsubstituted alkyl having from 1 to 18carbon atoms, cyclopentyl,

9. The process of claim 7 wherein reaction is made to take place in anaqueous medium.

10. The process of claim 7 wherein reaction is made to take place in thepresence of an inert organic solvent.

11. The process of claim 7 in which the (iso)cyanic acid reactant isgenerated in situ from an alkali metal isocyanate in the presence of anacid.

References Cited by the Examiner UNITED STATES PATENTS 3,116,315 12/63Rauhut 260-557 XR 3,116,316 12/63 Rauhut 260-557 XR 3,157,701 11/64Speziale 260-558 CHARLES B. PARKER, Primary Examiner.

Patent Noe 5,214,457 October 26, .1965

Grace Peters Papp et alu It is hereby certified that error appears inthe above numbered patent requiring correction and that the said LettersPatent should read as corrected below.

Column 1, lines 12 to 14, the formula should appear as shown belowinstead of as in the patent:

R R PCONH Signed and sealed this 5th day of July 1966! Attesting OfficerCommissioner of Patents UNITED STATES PATENT OFFICE CERTIFICATE OFCORRECTION Patent No. 3,214,457 October 26, 1965 Grace Peters Papp et a1It is hereby certified that error appears in the above numbered patentrequiring correction and that the said Letters Patent should read ascorrected below.

Column 1, lines 12 to 14, the formula should appear as shown belowinstead of as in the patent:

L n R R CONI-I Signed and sealed this 5th day of July 1966.

(SEAL) Attest:

ERNEST W. SWIDER EDWARD J. BRENNER Attesting Officer Commissioner ofPatents

1. A MONOCARBAMOYL-SUBSTITUTED TERTIARY ORGANIC PHOSPHINE OF THE FORMULA